(1) Field of Invention
The present invention relates to a hibernation system for a computer, in which the previous operating condition is initiated by input from a peripheral device such as a keyboard. Particularly, in a hibernation system which cuts off power automatically when one does not use the computer for a period of predetermined duration, the present invention relates to a power control device which can retrieve the operating environment to the previous state by supplying the power again if a key-signal input by a user or a signal from a modem or other peripheral device is input.
(2) Description of Prior Art
With the progression of computer functionality, and in consideration of energy conservation, power-saving functions of computers have been improved so as to include hibernation systems.
A desirable hibernation system includes a function that in case electrical power is cut off through either sudden power failure or a mistake made by a user, the computer stores the present operation condition in an auxiliary storage unit such as a hard disk and once power is on again, restores the computer's memory to the pre-power-off state. Another desirable function is that in case a user does not use the computer for a predetermined time when the computer is in a power-on state, the hibernation system cuts off the power automatically while storing the present operating condition in the auxiliary storage unit. Electrical power is economized, until work is resumed by retrieving to the computer's memory the operating condition stored in the auxiliary storage unit to that of the pre-power-off state when the user turns on the power again.
Among conventional personal computers, hibernation systems equipped with automatic retrieving functions for emergency or power saving use are increasingly popular.
Korean Patent Application No. 93-3116, filed on Mar. 4, 1993 relates to a power supply control system for peripheral equipment of a computer, and Korean Patent Application No. 92-14590, filed on Aug. 13, 1992 relates to a power cut off generating circuit for peripheral equipment of a computer.
However, these prior hibernation systems reduce a power-supply to below certain voltages when the computer receives no input from a user for a predetermined time. Therefore, the user must turn-on power the switch twice to supply electrical power again and retrieve their work to its previous condition. This creates an inconvenience in operating the computer.